Congestive heart failure is the symptomatic description of end organ failure of the heart muscle to act as a pump. The failure of the heart to pump blood leads to accumulation of fluid or congestion in the body areas from which the blood was to be pumped. In the case of right ventricular failure, the consequence is systemic edema often manifest initially by symptomatic dependent edema at peripheral sites (e.g. ankles). In the case of left ventricular failure, the fluid accumulation occurs in the lungs and is manifest by pulmonary edema, the primary symptom of which is shortness of breath. Left heart failure is more common and important because of its relative size and the physiologic function of providing systemic circulation to critical organs.
The primary underlying cause of heart failure (low output failure) is coronary artery disease leading to myocardial infarction and cardiac muscle death. Additional pathologies include cardiomyopathies and myocarditis, valvular dysfunction, metabolic and endocrine abnormalities (e.g., hypothyroidism, alcohol, Mg deficiency etc.) pericardial abnormalities.
In 1992, Conjestive Heart Failure (CHF) prevalence was estimated to be approximately 1% of the general population, 6.8% of patients over the age of 65, and 0.2%-0.4% of the managed care population (prior to the active recruiting of senior members). In absolute numbers, this represents approximately 2.76 million patients in the USA. Subclassification by severity provides estimates of 10% as severe, 40% moderate, and the remainder mild. New cases of diagnosed CHF are expected to increase 29%, from 495,7000 per year in 1992 to 642,000 by the year 2007. This increase can be attributed to several factors, including the general aging of the population, as well as improvements in physician awareness and diagnostic techniques.
There has been a marked increase in the number of seniors enrolling in managed care plans (MCOs). In some plans, seniors can account for up to 50% of total enrollment. In addition, the number of seniors enrolled in Medicare risk programs is projected to grow by 28% to 2.3 million by the end of 1995. Growth in Medicare risk programs is expected to continue, due to the anticipated passage of the Medicare reform bill, which will encourage seniors to join health plans. Also, the current "50/50" provision that forces MCOs to enroll one non-Medicare patient for every Medicare patient enrolled may be overturned, which will make it easy for plans to concentrate on Medicare patients.
Patients with CHF are living longer as treatment options increase. This means that MCOs will need to be able to cost-effectively manage CHF for an ever-growing number of patients. This is made apparent by several other facts. CHF was the most expensive health care problem according to the Healthcare Financing Agency (HCFA) in 1992. Approximately 5.45 billion dollars were spent on hospitalization, or 4.8% of the total Diagnositc Related Group (DRG) budget. CHF is also the single most frequent cause of hospitalization for people age 65 and older. As was previously noted, it is projected that one percent of the general population has CHF, which translates to 6.8% of the elderly. Interestingly, even in MCOs that do not actively recruit seniors, CHF can account for up to 2% of the overall MCO medical loss rate.
Treatment of CHF is primarily symptomatic through three pathophysiologic mechanisms:
1. Afterload reduction--Reduction of the resistance against which the heart must pump blood. Primarily achieved pharmacologically although in severe situations aortic counter pulsation is used.
2. Cardiac Inotropic state--Improvement of the efficiency of the heart through pharmacological agents acting directly on myocardium (e.g. cardiac glycosides), reduction in starling equilibrium's through chamber size reduction and improvement in coronary artery blood flow.
3. Pre-load reduction--Reduction in the volume of blood entering the heart. This can be achieved through pharmacological interventions (diuretics, vasodilators), dietary (salt and water restriction) and physical means (rotating tourniquets, blood volume reduction).
The primary pharmacological interventions, therefore, consist of agents from three primary classes, diuretics, cardiac glycosides and Angiotersin Converting Enzyme (ACE) inhibitors. In addition, recent studies have shown benefit from the use of beta-blockers with anti-oxidant properties. Ultimately, cardiac transplantation now offers an alternative to terminal life threatening heart failure.
The complexity of care required, as outlined above, indicates the need for substantial physician and patient involvement in the optimal management of the condition including the appropriate selection and use of pharmacological interventions and the modification of individual life styles to achieve best results from interventions.
Obviously, an overall objective of any CHF Disease Management Program should be to improve the quality of treatment and outcomes for patients with CHF while, at the same time, achieving cost savings. An important step in doing so is to identify patients who are at high risk of adverse outcomes and assuring "best practice" treatment of these patients. There is, therefore, a real need to identify patients who are at high risk of hospitalization for CHF.